The Tufftride QPQ process (quench, polish, quench) is a specialised surface treatment that builds on the standard Tufftriding/nitrocarburising procedure by incorporating additional steps to enhance surface hardness, wear resistance, and corrosion resistance. The process is particularly favoured in industries that require durable and long-lasting components, such as automotive, aerospace, and machinery manufacturing.
The basic Tufftriding or nitrocarburising process is a thermochemical treatment that involves diffusing nitrogen and carbon into the surface of steel or iron parts. This process improves components’ wear resistance and fatigue strength while providing some corrosion resistance. However, further protection and enhanced surface properties are required in certain applications.
After Tufftriding/nitrocarburising, a post-oxidation treatment can be applied, often referred to as blackening or Oxynit. This involves quenching the parts into a bath containing oxidising salts. During this step, a corrosion-resistant magnetite (Fe3O4) layer forms on the surface, giving it a distinctive black colour. This magnetite layer provides additional corrosion protection, making it ideal for components exposed to harsh environmental conditions.
The Tufftride QPQ process is an enhanced version of the standard Tufftriding treatment. After the initial post-oxidation quenching, the QPQ process introduces an intermediate polishing stage. This polishing step improves the surface finish by smoothing any imperfections that may have arisen during the oxidation process, resulting in a more uniform and aesthetically pleasing appearance.
After polishing, the parts are returned to the furnace for a second quenching in the AB1 (oxidising) bath. This additional step further strengthens the magnetite layer and improves the treated part’s overall surface properties.
The Tufftride QPQ process offers several significant advantages over traditional nitrocarburising or Tufftriding, particularly in terms of durability, performance, and aesthetics:
The Tufftride QPQ process is a powerful surface treatment solution for industries that demand the highest wear and corrosion resistance standards. Its ability to create a durable, smooth, attractive finish makes it a go-to choice for many applications.
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